Carrier 50ZHK, Installation Instructions Manual, Page: 8 / 22

50ZHK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Routing Power Leads into Unit
Use only copper wire between disconnect and unit. The high-voltage
leads should be in a conduit until they enter the unit; conduit termination
at the unit must be watertight. Run the high-voltage leads through the
hole on the control box side of the unit (See Fig. 10 ). When the leads are
inside the unit, run leads to the control box (See Fig. 11 ). Connect leads
to the black and yellow wires (See Fig. 12 ).
A08407
Fig. 10 – Unit Electrical Connection
A10031
Fig. 11 – Control Box Wiring
A10022
Fig. 12 – Line Power Connections
Connecting Ground Lead to Unit Ground
Connect the ground lead to the chassis using the unit ground in the
control box (See Fig. 11 and Fig. 12 ).
Routing Control Power Wires (24-V)
Form a drip-loop with the thermostat leads before routing them into the
unit. Route the thermostat leads through grommeted hole provided in
unit into unit control box (See Fig. 10 ). Connect thermostat leads and
unit power leads as shown in Fig. 12 - Fig. 15 .
The unit transformer supplies 24-v power for complete system including
accessory electrical heater. Transformer is factory wired for 230-v
operation.
Unit main harness contains a 3 amp automotive style replaceable fuse. If
transformer secondary voltage is not available at red and brown leads in
unit low voltage box, check fuse in red lead near transformer. Replace
with Littelfuse brand, part number 257003.
Unit main harness also contains a 1k ohm, 3 watt load resistor wired
across low voltage leads “G” and “C”. Purpose of resistor is to provide a
small electrical load for the indoor thermostat fan circuit to ensure
reliable operation.
Accessory Electric Heat Wiring
Refer to accessory electric heat installation instructions for information
on installing accessory electric heat. Accessory electric heat wiring is
shown in Fig. 14 - Fig. 16 .
NOTE: When installing an accessory electric heater, the high voltage
wire harness pass-through must be sealed with silicone or equivalent at
the partition in order to comply with the 2% or less air leakage
certification.
Pre-Start-up
Proceed as follows to inspect and prepare the unit for initial start-up:
1. Remove all access panels.
2. Read and follow instructions on all DANGER, WARNING,
CAUTION, and INFORMATION labels attached to, or shipped
with unit.
HIGH-VOLTAGE POWER
WIRING ENTRY HOLE
LOW-VOLTAGE WIRING
ENTRY HOLE
(grommet hole)
Electric Heat wiring
interconnection (electric
heater controls removed
for clarity)
Electric Heat Control Box
(shown uninstalled)
SINGLE-PHASE
CONNECTIONS
TO DISCONNECT
PER NEC
GROUND
LEAD
UNIT GROUND
BLK
YEL
L
L
EQUIP GR
WARNING
!
FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death
and/or property damage.
1. Follow recognized safety practices and wear protective goggles
when checking or servicing refrigerant system.
2. Relieve and recover all refrigerant from system before touching or
disturbing compressor plug if refrigerant leak is suspected around
compressor terminals.
3. Never attempt to repair soldered connection while refrigerant
system is under pressure.
4. Do not use torch to remove any component. System contains oil
and refrigerant under pressure.
5. To remove a component, wear protective goggles and proceed as
follows:
a. Shut off electrical power to unit and install lockout tag.
b. Relieve and reclaim all refrigerant from system using both high-
and low-pressure ports.
c. Cut component connecting tubing with tubing cutter and
remove component from unit.
d. Carefully unsweat remaining tubing stubs when necessary. Oil
can ignite when exposed to torch flame.